Although a wide variety of crystal structures are known in nature, any specific material usually has a single preferred crystal structure in which it can be grown. In some cases, it would be desirable to have control over the crystal structure of a grown material, as opposed to being limited to a single fixed crystal structure. For example, gallium phosphide (GaP) normally crystallizes in the zincblende crystal structure. The zincblende crystal structure is one of the crystal structures included in the cubic system of crystal structures. Unfortunately, zincblende GaP has an indirect band gap, which limits its utility for optoelectronic device applications.
Theoretical predictions from band structure calculations suggest that GaP would have a direct band gap if it were to crystallize in the wurtzite crystal structure. The wurtzite crystal structure is one of the crystal structures included in the hexagonal system of crystal structures. Gallium phosphide having a direct band gap would be useful for various optoelectronic device applications. However, to date there has been no report of growth of GaP in the wurtzite crystal structure with a direct band gap. Accordingly, it would be an advance in the art to provide growth of wurtzite GaP having a direct band gap.